A termination bar is a preformed strip, plastic or extruded aluminum, predrilled so fasteners land on a regular grid, used to clamp the top edge of a waterproofing membrane to a vertical substrate [S1][S4][S6].
Counterflashing is a separate metal or membrane cover that laps over the bar and the membrane top, shedding water away from the fasteners. Building codes require the two to be used together at wall terminations: a bar without counterflashing leaves the seal exposed to UV and wind-driven rain, and a counterflashing without a bar leaves the membrane mechanically loose [S3][S5].
What each component does, and why the pair is non-negotiable
W. R. Meadows describes its TERMINATION BAR as a "preformed plastic attachment strip used to neatly and securely anchor waterproofing membranes, drainage boards, and flashing materials at their top edges, especially in vertical applications," supplied as 10-foot lengths predrilled every 6 inches for fastener scheduling [S1]. Henry's equivalent is an extruded aluminum bar designed for "securing and sealing compression type flashing terminations" on EPDM and TPO systems [S4]. Sika's Sikaplan variant is a flat aluminum bar with a 45° lip that forces water to drop away from the wall face, used with approved fasteners to terminate single-ply membranes at walls and roof edges [S6].
Counterflashing's job is water-shedding, not sealing. Bauder's product page frames its termination bar as an "alternative to lead counterflashing for use at upstand details to give protection to the top edge of the waterproofing" [S2]. The RCABC PVC membrane detail (Drawing E) carries the principle one step further: a surface reglet counterflashing with a kicked-out top edge, sealed with a gunnable sealant bead, "to form a waterproof seal with the wall" [S7]. Without that outer cover, the exposed sealant joint above the bar is the first thing to fail under thermal cycling and UV.
Code-level geometry: bar height, fastener spacing, and pull-out
The prescriptive requirements are concrete, not opinion. The membrane base flashing section carried at UpCodes sets the spacing, edge offset, and pull-out force that any compliant termination must meet [S5]:
Continuous metal termination bar fastened at 6 in. on center to the vertical wall.
Bar placed no more than 1 1/2 in. down from the upper edge of the membrane flashing.
Membrane flashing terminates under a metal counterflashing, or finishes with a surface-mounted reglet attached at spacing not to exceed 8 in. on center, weatherproofed with a caulk bead bonded to both metal and wall.
Anchors must deliver a minimum 150 lbf characteristic resistance (TAS 105), or a 150 lbf average withdrawal after a 2:1 margin of safety is applied, installed through slotted or oversized holes to accommodate movement.
Base flashing height is also fixed: not less than 8 in. above the finished roof surface, with a 4 in. relaxation only when existing job conditions prevent the 8 in. rise [S5]. The same code section mandates a cant strip at every vertical junction and caps exposed membrane angle change at 45 degrees unless the manufacturer's published detail covers it [S5].
Material and profile options: plastic, aluminum, lipped, reglet
Four formats cover most field conditions, and the trade-offs are well-defined [S1][S2][S4][S6][S7]:
Preformed plastic bar (Meadows): non-corrosive, UV-resistant, 10 ft lengths, 6 in. fastener pattern. Lowest cost per foot, used where the membrane will be concealed or backfilled soon after install.
Extruded aluminum bar (Henry, Sika): higher pull-out strength, compatible with contact adhesives and hot-air welding of TPO/PVC, often supplied with a 45° drip lip (Sikaplan) to throw water clear of the wall.
Lead or lead-free alternative counterflashing (Bauder): traditional upstand protection, replaced in many specifications by aluminum or PVC-coated metal for health-and-environment reasons.
Surface reglet counterflashing (RCABC Detail E): two-piece metal, top edge "kicked out" and sealed, used where a reglet saw-cut into the masonry is impractical, for example on hollow CMU or pre-finished cladding.
Selection is driven by substrate (masonry, precast, tilt-up, CMU, EIFS), membrane chemistry (bituminous, EPDM, TPO, PVC, modified bitumen), and exposure (UV, foot traffic, plaza deck). For a primer on the underlying sheet materials these bars clamp, see the modified bitumen membrane reference and the broader waterproof membrane family page.
Substrate pitfalls: where the detail leaks even with a perfect bar
A correctly fastened bar on the wrong wall still leaks. The 2023 Roofing Magazine field review of terminations and counterflashing flagged the recurring failure modes a roofer actually walks into [S3]:
Masonry: weeps and through-wall flashing must remain unblocked. If the new insulation height buries them, raise the through-wall flashing first; otherwise water resurfaces behind the base flashing.
Control joints: sealant control joints above the roof open under thermal movement and route water straight to the termination. The bar and counterflashing must "float" over these joints, not bridge them rigidly.
Precast and tilt-up panels: panel joints are typically beveled, which makes a clean reglet cut and a continuous sealant bead hard to achieve. Cohesive sealant failure inside the joint is common and visible as splitting along the bead.
Substandard masonry: "Placing a termination bar and counterflashing on substandard masonry walls may look good but will not prevent water intrusion" [S3]. The wall behind the base flashing needs inspection and often restoration before the new roof goes on.
Field guidance is consistent on the top-line point: "A termination bar should never be installed without counterflashing" [S3]. The product literature is right there in the same direction, with manufacturers offering matching counterflashing or reglet systems rather than letting the bar sit exposed [S2][S4][S6][S7]. For the larger envelope strategy that this detail sits inside, the thermal and waterproofing systems overview is a useful reference.
Movement, sealant, and the role of the cant strip
Parapet and upstand details move more than the field of the roof. Clamping a membrane rigidly at the top of a wall, with fasteners through unslotted holes, locks the sheet into the wall's expansion and contraction and tears it within a few seasons. The code language fixes this directly: anchors go through "slotted or oversized holes" so the bar can slide as the structure moves, and the 150 lbf pull-out requirement is paired with a 2:1 safety margin precisely because the wall is alive [S5].
The cant strip is the second movement-management device. By beveling the 90° transition between deck and upstand, it lifts the membrane off the sharp inside corner where it would otherwise crease and crack. The 45° maximum exposed-angle rule is the upstream guard for the same problem on taller upstands [S5]. A 45° drip lip on a bar profile (Sikaplan) is the matching downstream device: it kicks water away from the wall face so the bar and the sealant joint above it stay dry between rain events [S6].
Sealant choice is the third leg. The RCABC PVC detail calls out a gunnable bead at the top of the reglet that bonds to both the metal and the wall substrate, with the expectation that this joint is a maintenance item, not a permanent seal [S7]. On bituminous systems, metal terminations must be fully primed with ASTM D41 primer before the membrane is bonded to them, and bituminous flashing may be built up as multi-ply felts or as a modified bitumen flashing sheet per the membrane manufacturer's published detail [S5].
Specifying the detail: a short checklist for a submittal package
Most rejections at plan review come from missing one of the following. A complete termination and counterflashing submittal should carry, at minimum [S1][S2][S4][S5][S6][S7]:
Bar material and profile: plastic (Meadows type), extruded aluminum, or aluminum with 45° drip lip; bar dimensions and length per piece.
Fastener type, diameter, length, and substrate suitability: matching the 150 lbf pull-out requirement at 6 in. o.c. through slotted or oversized holes [S5].
Bar position: 1 1/2 in. maximum down from the top edge of the membrane, with membrane base flashing rising not less than 8 in. above finished roof surface (4 in. minimum only where existing conditions prevent 8 in.) [S5].
Counterflashing or reglet: surface-mounted reglet at 8 in. o.c. with a caulk bead, or a through-wall reglet with a kicked-out top edge and gunnable sealant [S5][S7].
Movement strategy at control joints, expansion joints, and inside corners: bar floats, sealant bridges, reglet terminates short of the joint.
Substrate preparation: ASTM D41 primer for asphaltic systems bonded to metal, masonry restoration scope if the wall behind the flashing is substandard [S3][S5].
For the broader sheet-to-sheet termination logic and how deck-to-wall terminations differ from parapet upstands, the deck-to-wall membrane termination guide covers the laps and edge-metal sequence side of the same problem. Where the termination meets a below-grade wall or a plaza-deck-to-building transition, the below-grade versus plaza deck waterproofing matrix is the matching reference, and the footing-to-wall cold joint detailing page handles the waterstop side at the base of the wall.
Trackable signals for the next planning cycle: code-body revisions to the 150 lbf anchor pull-out threshold and the 6 in. termination-bar fastener spacing in the membrane base flashing section; and the wider industry move away from lead counterflashing toward aluminum and PVC-coated alternatives that Bauder and others now stock as standard [S2][S5].